Bimetallic Ni-Co Silicate Hollow Spheres with Controllable Morphology for the Application on Supercapacitor

Abstract

A facile and one-step synthetic method is developed to produce the layered bimetallic Ni−Co silicate with the controllable morphology and porous microstructure by using the silica as the sacrifice template at the moderate reaction conditions. The bimetallic Ni−Co silicate core-shell and hollow spheres were obtained under 140 °C for 6 h and 12 h, respectively. The pore size and the content of metal ions of the bimetallic Ni−Co silicate could be affected by the different structure. The final product shows good dispersivity, which is benefit to the homogeneity as an active material in the electrode. The as-prepared Ni−Co silicate hollow spheres exhibit good electrochemical performance with high specific capacitance and rate capability, good charge-discharge stability and long cycle life. The capacitance retention of the hollow structure can reach 58.69% at the current density of 10 A/g and 86.38% after 5000 cycle. The good electrochemical performance can be attributed to the different size of the pores and layer architecture. Bimetallic Ni−Co silicate hollow spheres show better electrochemical properties than the monometallic Ni or Co, which attribute to the synergistic effect.